Conventionally, for example, Wake-on-LAN (WOL) described in Japanese Laid-open Patent Publication No. 2000-209220 is available as a function of remotely operating a personal computer, a server, and the like. WOL is a technique of activating a computer that is connected to a local area network (LAN) when this computer is in an inactive state by controlling from another computer connected to the same LAN. By using WOL, for example, an administrator of the network may manage a computer at a remote site by operating a computer present nearby.
To use WOL, a network card, a motherboard, a basic input/output system (BIOS), an OS, and the like of a computer to be activated should support WOL.
In recent years, a virtual machine (VM) that allows more than one OS to operate on a single computer is attracting attentions. In a virtual machine, a host OS that is activated first when the computer is turned on and a guest OS that operates on the host OS may operate at the same time. Therefore, it becomes possible to use software that may work only on a certain OS also in hardware that uses another OS as the host OS.
When WOL is applied to such a virtual machine, generally, the computer is turned on, and the host OS is activated. However, a guest OS installed in the computer is not activated, and it is difficult to manage a guest OS from a remote site.
Particularly, more than one guest OS may be installed in a single computer. Therefore, just by instructing activation from a remote site through a network, it may not be specified which guest OS should be activated, and a problem peculiar to a virtual machine occurs.
In addition, to save computer resources, it is preferable that an unnecessary guest OS should be stopped even in a state where the host OS is activated. However, if a guest OS is stopped once, activation using WOL is impossible in a present situation. Accordingly, an unnecessary guest OS can be kept active, preparing for a remote operation.